An ATM-PON (“Asynchronous Transfer Mode”—“Passive Optical Network”) architecture has been developed for the cost-effective deployment of optical fiber in an access network, whereby to permit communications between a central office and a downstream station. The ATM-PON architecture uses bi-directional transmission between the central office and the downstream station, with 1.5 μm being the wavelength for the downstream transmission and 1.3 μm being the wavelength for the upstream transmission. Passive Optical Network (“PON”) refers to the use of splitters/combiners to passively split or combine optical signals without requiring conversion of those optical signals to corresponding electrical signals.
In the ATM-PON architecture, all downstream stations have access to the same bandwidth. Downstream transmission is in a broadcast mode, while upstream transmission is in a time division multiplex (“TDM”) mode, with each downstream station being assigned a specific time slot for sending its upstream signal to the central office.